Objectives: Chronic kidney disease (CKD) is a comorbidity in psoriatic arthritis (PsA). We aimed to define the prevalence of CKD in patients with PsA, describe their long-term renal outcomes and identify risk factors for CKD development.
Methods: We included patients with PsA followed by our prospective observational cohort. We defined CKD as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 for at least 3 months. We characterised long-term renal outcomes of CKD cases identified following clinic entry. We used time-dependent Cox regression models to identify factors associated with CKD development.
Results: Of 1336 patients included in the study, 123 (9.2%) had CKD. Of these, 25 (20.3%) were observed to have CKD at clinic entry and 98 (79.7%) developed CKD during follow-up at a median (IQR) of 8.2 (2.8-14.0) years from baseline. Doubling of baseline creatinine was observed in 18 of 98 (18.3%) new patients with CKD. 49 (50%) patients developed a sustained ≥40% reduction in baseline eGFR. Two patients developed eGFR <15 mL/min/1.73 m2. In the multivariate Cox regression model adjusted for age at study entry, sex and baseline eGFR, factors independently associated with the development of CKD included diabetes mellitus (HR 2.58, p<0.001), kidney stones (HR 2.14, p=0.01), radiographic damaged joint count (HR 1.02, p=0.02), uric acid (HR 1.21, p<0.001; 50-unit increase), daily use of non-steroidal anti-inflammatory drugs (NSAIDs) (HR 1.77, p=0.02) and methotrexate use (HR 0.51, p=0.01).
Conclusion: CKD is not infrequent in PsA. Its development is associated with related comorbidities, joint damage and NSAID use. Methotrexate seems to be protective.
Keywords: Anti-Inflammatory Agents, Non-Steroidal; Methotrexate; Psoriatic Arthritis.
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